African-American women are at greater risk of being assaulted by intimate partners than any other group of women. New research presented yesterday by the Johns Hopkins Bloomberg School of Public Health suggests that harm from abuse doesn’t end with the violence itself.

Intimate partner violence often increases during pregnancy when women are most vulnerable, according to Dr. Samantha Meltzer-Brody, director of the perinatal psychiatry program at University of North Carolina.

In addition to the danger that abuse poses to the woman and her unborn child, the Johns Hopkins study shows that these women are also at greater risk of postpartum depression. According to the data, one out of every three women abused during pregnancy went on to develop depression in the first 12 months of the child’s life.

Intimate partner violence can include anything from sexual abuse, physical abuse, or stalking to pregnancy coercion — when a woman is forced to conceive a child against her will.

Some experts have speculated that postpartum depression linked to abuse from her partner may have led to Newburgh mom Lashanda Armstrong’s murder-suicide, in which she killed her 11-month-old, 2-year-old and 5-year-old children.

“Postpartum depression can occur up to a year postpartum, so whenever you hear a story of erratic behavior, withdrawal, violence toward one’s own children, it fits with [it],” said Dr. Gail Saltz, associate professor of psychiatry at New York Presbyterian Hospital and Today Show contributor. “Guilt is also a big feature of postpartum depression.”

Individually, both intimate partner violence and postpartum depression can prevent a woman from forming a strong mother-infant bond. This bond is important to the child’s continued health, educational development and behavioral control. Postpartum depression, in particular, can lead to substantial neglect, or even violent acts against the infant, if depression becomes severe or the new mother displays psychotic symptoms.

In a CNN interview, Darice Armstrong, Lashanda Armstrong’s sister, describes her sister’s paranoid behavior. “She was talking to me about how she felt like somebody was watching her,” Darice explained. ”[And that] the lights in her house were flickering on and off.”

Stories like Lashanda Armstrong’s are real, but rare, experts say. More commonly, postpartum symptoms range from “baby blues” with mild sadness, fatigue and increased crying, to feelings of worthlessness and guilt. It can be hard to differentiate the normal changes of new motherhood from postpartum depression.

And, it is often a challenge for women to admit they need help.

“When they have the feeling that ‘I don’t like my baby,’ ‘I don’t want to be a mother,’ or ‘I’m a terrible mother,’ ‘I have a terrible baby,’ they feel ashamed,” Saltz said.

An estimated 80 percent of women develop depression after delivering a child, yet the disorder frequently goes undiagnosed. Given the stigmas around mental health disorders in the African-American community, African-American women are diagnoses even less.“If there isn’t family that understands what postpartum depression is, or recognizes that that’s what they’re seeing, or if there is no family around, it will greatly increase the odds,” said Saltz.

On a biological level, postpartum depression is thought to be caused by the drastic drop in hormones upon delivering, and exacerbated by sleep deprivation. If a woman previously had significant depressive symptoms with menstrual periods, or ever had depression in the past, she is more likely to develop postpartum depression.

It is also well understood in the medical community that any psychological or physical trauma increases the odds of developing depression later on, which is likely the connection between intimate partner violence and postpartum depression.

In addition to this link, within the African-American community, little access to affordable treatment, lower socioeconomic status, substance abuse, scarce involvement by the child’s father, and limited social support are key factors.

“Eighty-five percent of postpartum depression can be relieved by social support and [only] 15 percent needs medications,” said Dr. Carl C. Bell, President and CEO of Community Mental Health Council in Chicago.

In an abusive relationship, the perpetrator usually does not provide a source of support and ultimately isolates the victim from her family and friends, which decreases her amount of social support even further, added Bell.

“Depression and domestic violence are two conditions that are greatly under-recognized and under-treated,” Cheng said. “This is unfortunate, because there is effective treatment for depression and there are many resources for women to get help with intimate partner violence.”